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Not Applicable.
The present invention relates to fuel system components such as, for example, fuel vapor flow control valves for use in liquid fuel tanks employed in motor vehicles. In present production of passenger and light truck vehicles, it is required to have valves for controlling the flow of fuel vapor from the fuel tank to a storage canister and also to provide valves capable of closing the vent in the event the vehicle is tipped beyond a threshold amount or rolled from the upright position. In providing such components in vehicle fuel tanks, problems have been encountered in forming the components of materials which are acceptably dimensionally stable when immersed in the fuel and yet which are compatible with the fuel tank. The choice of the materials for the fuel tank is generally dictated by the fabricating processes employed and a need for materials which may be welded together. Unfortunately, it has been found that the properties of the materials employed for the components immersed in the fuel are not compatible with welding attachment to the fuel tank materials.
In order to provide attachment to the fuel tank of such fuel vapor system components in a manner which will produce a robust and leak-proof attachment, it has been desired to weld the components onto the tank after assembly over an access opening in the tank. Thus, the material of the attached external component must be weldable to the tank material. Where the tank is formed of resinous or plastic material, it has been found virtually impossible to match the properties of the interior immersed components with those of the attachment components and to provide the requisite mechanical and fuel resistant properties needed for the immersed components. Therefore, it has long been desired to provide a way or means of attaching fuel system components which are designed for immersion in the fuel to the remaining components of the system which are designed to be attached and secured onto the tank by weldment. The problem has been particularly acute in finding a way or means of attaching fuel vapor flow control valves and rollover valves to fuel tanks formed of plastic material.
The present invention provides a solution to the problem of attaching fuel system components to a fuel tank where the components intended to extend interiorly of the tank and immersed in the fuel are formed of different material from the components intended for attachment exteriorly of the tank and particularly those intended for attachment to the tank by weldment.
The present invention employs an exterior component formed of material suitable for weldment to a fuel tank and an interior component formed of different material suitable for prolonged immersion in the liquid fuel in the tank in which the interior component is attached to the exterior component prior to assembly onto the tank. The present invention employs an exterior component which has a plurality of projections or lugs extending downwardly therefrom in a spaced array; and, the interior component has a correspondingly spaced array of radially extending slots with the sides of the slots having engagement surfaces, preferably barbs formed thereon for push-in attachment over the lugs on the exterior component. The barbs are preferably of harder material and deform the lugs to retain them in position. The radial slots with their barbed edges permit swelling and expansion of the immersed component and sliding of the lugs on the barbs without weakening or loosening of the engagement of the barbs on the projecting lugs.